1. Field of the Invention
The present invention relates generally to heat-dissipating devices, and more particularly, to a heat pipe.
2. Description of the Related Art
A conventional heat pipe is usually composed of a sealed tubular member, a capillary wick mounted on an internal sidewall of the tubular member, and adequate liquid, employing the liquid-vapor variation and the flowage of the liquid for thermal conduction. In practical operation, water located at a heated section of the tubular member is heated to be transformed into vapor, the vapor is then diffused to a condensed section of the tubular member to be transformed into water, and then the water is returned to the heated section through the capillary action generated by the capillary wick, thus completing heat exchange. Such endless cycles of endothermic and exothermic reactions can effect rapid thermal conduction.
Referring to FIGS. 5 and 6, a conventional heat pipe 80 includes a plurality of ditches 82 formed on an internal sidewall thereof for capillary action. The capillary action of the ditches 82 enables flowage of liquid contained therein to cause liquid-vapor equilibrium and to further effect rapid thermal conduction.
However, the ditches 82 of the aforesaid heat pipe 80 have tiny cross-sectional area to cause less refluence of the water, thus incurring worse thermal conduction.
Referring to FIGS. 7 and 8, another conventional heat pipe 90 includes a capillary layer 94 mounted at an internal sidewall thereof for capillary action. The capillary layer 94 is made of sintered metallic grains and gaps are formed among the metallic grains. The capillary action is generated in the gaps to guide the liquid contained in the heat pipe 90 to further cause the liquid-vapor equilibrium, equally effecting rapid thermal conduction.
Although the cross-sectional area of the metallic grains of the aforesaid heat pipe 90 for capillary action is larger than that of the heat pipe 80, it is still insufficient for thermal conduction, thus requiring further improvement.